408 vibration

[FAT-N-FAST]

I now have about 700 miles on the little mistress and I have noticed that I have a vibration at 1800-1900 rpm anything above or below that rpm and its fine. Also trans is TKO60. Any Ideas

[2bking]

Do you have to be driving or is it there with just engine RPM while sitting still?

[Garry Bopp]

I've got a 422" Windsor and have always had a noticeable vibration right around 2000 rpm. Not terrible, but noticeable. I just try to keep the revs either above or below 2,000 rpm. 16,000+ miles plus at least a dozen track days. Still running strong.

Garry

[Dale Claytor]

I have a TKO 600 behind a 347 stroker and had exactly the same problem, vibration around 2000 rpms. Turns out the tail shaft housing on the tranny was resting on the frame. Didn't even have enough space to slip a business card in between. I put a couple of washers under the tranny mount to raise the rear of the tranny about 1/4 inch. Problem solved. Hope this helps.

Dale

QUOTE=FAT-N-FAST;119326]I now have about 700 miles on the little mistress and I have noticed that I have a vibration at 1800-1900 rpm anything above or below that rpm and its fine. Also trans is TKO60. Any Ideas[/QUOTE]

[Gordon Levy]

Could be wrong balance flywheel or balancer, wrong pilot bearing, no index dowel on the clutch. All of these would cause a 1800-2000 rpm vibration.

[Boz1911]

My 408 is internally balanced and takes a neutral balance flywheel and balancer. May want to double check you don't have any internal/external parts mixed up.

[Gordon Levy]

No all 408's are internally balanced

[first time builder]

Ditto on the trans tailshaft.
Kenny

[Boz1911]

No all 408's are internally balanced

Guess I didn't word my post correctly, meant did he accidently have an external balance part installed like the flywheel or balancer.........sorry

[FAT-N-FAST]

Changed rear diff lower control arm bolt position to lower pinion and reshimmed trans. thinking back this is about when vib started had no vibration before this change. will have to check pinion angles, Thanks for jogging memory. Pinion angle concept just seems to elude me.

[Gordon Levy]

The vibration is only when you are driving? Anything more than 1.5 degrees down can cause a vibration but I have seen that vibration get worse as speed goes up.